Chaffey Patrick K, Guan Xiaoyang, Chen Chao, Ruan Yuan, Wang Xinfeng, Tran Amy H, Koelsch Theo N, Cui Qiu, Feng Yingang, Tan Zhongping
Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado , Boulder, Colorado 80303, United States.
Shandong Provincial Key Laboratory of Energy Genetics and CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences , Qingdao, Shandong 266101, China.
Biochemistry. 2017 Jun 13;56(23):2897-2906. doi: 10.1021/acs.biochem.7b00195. Epub 2017 Jun 1.
Protein glycosylation has been shown to have a variety of site-specific and glycan-specific effects, but so far, the molecular logic that leads to such observations has been elusive. Understanding the structural changes that occur and being able to correlate those with the physical properties of the glycopeptide are valuable steps toward being able to predict how specific glycosylation patterns will affect the stability of glycoproteins. By systematically comparing the structural features of the O-glycosylated carbohydrate-binding module of a Trichoderma reesei-derived Family 7 cellobiohydrolase, we were able to develop a better understanding of the influence of O-glycan structure on the molecule's physical stability. Our results indicate that the previously observed stabilizing effects of O-glycans come from the introduction of new bonding interactions to the structure and increased rigidity, while the decreased stability seemed to result from the impaired interactions and increased conformational flexibility. This type of knowledge provides a powerful and potentially general mechanism for improving the stability of proteins through glycoengineering.
蛋白质糖基化已显示出具有多种位点特异性和聚糖特异性效应，但迄今为止，导致这些观察结果的分子逻辑一直难以捉摸。了解所发生的结构变化并能够将这些变化与糖肽的物理性质相关联，是朝着能够预测特定糖基化模式如何影响糖蛋白稳定性迈出的有价值的步骤。通过系统地比较里氏木霉来源的7家族纤维二糖水解酶的O-糖基化碳水化合物结合模块的结构特征，我们能够更好地理解O-聚糖结构对分子物理稳定性的影响。我们的结果表明，先前观察到的O-聚糖的稳定作用来自于向结构中引入新的键合相互作用和增加的刚性，而稳定性降低似乎是由于相互作用受损和构象灵活性增加所致。这类知识为通过糖基工程提高蛋白质稳定性提供了一种强大且可能通用的机制。
